21667325 has 6 divisors (see below), whose sum is σ = 26867514. Its totient is φ = 17333840.

The previous prime is 21667309. The next prime is 21667351. The reversal of 21667325 is 52376612.

It can be written as a sum of positive squares in 3 ways, for example, as 4044121 + 17623204 = 2011^2 + 4198^2 .

It is not a de Polignac number, because 21667325 - 2⁴ = 21667309 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21667291 and 21667300.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 433322 + ... + 433371.

It is an arithmetic number, because the mean of its divisors is an integer number (4477919).

Almost surely, 2^21667325 is an apocalyptic number.

21667325 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21667325 is a deficient number, since it is larger than the sum of its proper divisors (5200189).

21667325 is an equidigital number, since it uses as much as digits as its factorization.

21667325 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 866703 (or 866698 counting only the distinct ones).

The product of its digits is 15120, while the sum is 32.

The square root of 21667325 is about 4654.8173970630. The cubic root of 21667325 is about 278.7843771071.

The spelling of 21667325 in words is "twenty-one million, six hundred sixty-seven thousand, three hundred twenty-five".